Creating an OAI-PMH Feed From Your WebsitePosted: February 21, 2017 | Author: Margaret Heller | Filed under: data, web | Tags: Drupal, oai-pmh, wordpress | Leave a comment »
Libraries who use a flexible content management system such as Drupal or WordPress for their library website and/or resource discovery have a challenge in ensuring that their data is accessible to the rest of the library world. Whether making metadata useable by other libraries or portals such as DPLA, or harvesting content in a discovery layer, there are some additional steps libraries need to take to make this happen. While there are a number of ways to accomplish this, the most straightforward is to create an OAI-PMH feed. OAI-PMH stands for Open Archives Initiative Protocol for Metadata Harvesting, and is a well-supported and understood protocol in many metadata management systems. There’s a tutorial available to understand the details you might want to know, and the Open Archives Initiative has detailed documentation.
Content management tools designed specifically for library and archives usage, such as LibGuides and Omeka, have a built in OAI-PMH feed, and generally all you need to do is find the base URL and plug it in. (For instance, here is what a LibGuides OAI feed looks like). In this post I’ll look at what options are available for Drupal and WordPress to create the feed and become a data provider.
This is short, since there aren’t that many options. If you use WordPress for your library website you will have to experiment, as there is nothing well-supported. Lincoln University in New Zealand has created a script that converts a WordPress RSS feed to a minimal OAI feed. This requires editing a PHP file to include your RSS feed URL, and uploading to a server. I admit that I have been unsuccessful at testing this, but Lincoln University has a working example, and uses this to harvest their WordPress library website into Primo.
If you use Drupal, you will need to first install a module called Views OAI-PMH. What this does is create a Drupal view formatted as an OAI-PMH data provider feed. Those familiar with Drupal know that you can use the Views module to present content in a variety of ways. For instance, you can include certain fields from certain content types in a list or chart that allows you to reuse content rather than recreating it. This is no different, only the formatting is an OAI-PMH compliant XML structure. Rather than placing the view in a Drupal page or block, you create a separate page. This page becomes your base URL to provide to others or reuse in whatever way you need.
The Views OAI-PMH module isn’t the most obvious module to set up, so here are the basic steps you need to follow. First, enable and set permissions as usual. You will also want to refresh your caches (I had trouble until I did this). You’ll discover that unlike other modules the documentation and configuration is not in the interface, but in the README file, so you will need to open that out of the module directory to get the configuration instructions.
To create your OAI-PMH view you have two choices. You can add it to a view that is already created, or create a new one. The module will create an example view called Biblio OAI-PMH (based on an earlier Biblio module used for creating bibliographic metadata). You can just edit this to create your OAI feed. Alternatively, if you have a view that already exists with all the data you want to include, you can add an OAI-PMH display as an additional display. You’ll have to create a path for your view that will make it accessible via a URL.
The Views OAI-PMH module only supports Dublin Core at this time. If you are using Drupal for bibliographic metadata of some kind, mapping the fields is a fairly straightforward process. However, choosing the Dublin Core mappings for data that is not bibliographic by nature requires some creativity and thought about where the data will end up. When I was setting this up I was trying to harvest most of the library website into our discovery layer, so I knew how the discovery layer parsed OAI DC and could choose fields accordingly.
After adding fields to the view (just as you normally would in creating a view), you will need to select settings for the OAI view to select the Dublin Core element name for each content field.
You can then map each element to the appropriate Dublin Core field. The example from my site includes some general metadata that appears on all content (such as Title), and some that only appears in specific content types. For instance, Collection Description only appears on digital collection content types. I did not choose to include the body content for any page on the site, since most of those pages contain a lot of scripts or other code that wasn’t useful to harvest into the discovery layer. Explanatory content such as the description of a digital collection or a database was more useful to display in the discovery layer, and exists only in special fields for those content types on my Drupal site, so we could pull those out and display those.
In the end, I have a feed that looks like this. Regular pages end up with very basic metadata in the feed:
<metadata> <oai_dc:dc xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> <dc:title>Hours</dc:title> <dc:identifier>http://libraries.luc.edu/hours</dc:identifier><dc:creator>Loyola University Libraries</dc:creator></oai_dc:dc> </metadata>
Whereas databases get more information pulled in. Note that there are two identifiers, one for the database URL, and one for the database description link. We will make these both available, but may choose one to use only one in the discovery layer and hide the other one.
<metadata> <oai_dc:dc xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> <dc:title>Annual Bibliography of English Language and Literature</dc:title> <dc:identifier>http://flagship.luc.edu/login?url=http://collections.chadwyck.com/home/home_abell.jsp</dc:identifier> <dc:subject>Modern Languages</dc:subject> <dc:type>Index/Database</dc:type> <dc:identifier>http://libraries.luc.edu/annual-bibliography-english-language-and-literature</dc:identifier> <dc:creator>Loyola University Libraries</dc:creator> </oai_dc:dc> </metadata>
When someone does a search in the discovery layer for something on the library website, the result shows the page right in the interface. We are still doing usability tests on this right now, but expect to move it into production soon.
I’ve just touched on two content management systems, but there are many more out there. Do you create OAI-PMH feeds of your data? What do you do with them? Share your examples in the comments.